Four 'basic principles’ that may have led to the gruesome death of 'Grizzly Man' and his partner

As well as leaving a lasting legacy of his love for bears, Timothy Treadwell also left a something of an instruction manual for how not to interact with the animals when he passed away.

The outdoors enthusiast, who was nicknamed 'Grizzly Man' due to his affection for the mammals, met a gruesome end during one of his more than a dozen trips to Alaska.

The New York-native flew out to to the US state every summer for 13 years to get up close and personal with the animals, studying their behaviour and camping out alongside them.

He felt more at home among the furry creatures than anywhere else in the world and reckoned he had managed to make himself 'one of them' after his repeated trips.

The environmentalist and documentary maker's 2003 trip to Alaska would be his last though, as in a scenario which he seemingly predicted, Treadwell was killed by the things that he loved the most.

He was last heard from on 5 October that year, before pilot Will Fulton found the mangled remains of him and his girlfriend, Annie Huguenard, strewn across a campsite.

Treadwell - who would play with, touch and closely observe the bears - and his partner were visiting Katmai National Park to camp with the animals.

But just hours before the couple were due to fly back home via seaplane, he was mauled to death - and the bear then turned on Huguenard and killed her too.

Chillingly, Treadwell's camera captured six minutes of audio from the attacks, where he is frantically heard yelling at his other half to 'hit the bear'.

The animal lover screams: "Get out here! I’m getting killed out here!"

Pilot Fulton then arrived to collect them - but instead stumbled across a bizarre scene, consisting of a collapsed tent, unopened snacks, a finger, an arm, Treadwell’s skull and part of his spine attached.

Timothy Treadwell's love of bears ended up costing him his life. (Lionsgate Films)

A documentary of the couple's horror deaths, titled Grizzly Man, was later released, which was made up of footage that the Grizzly Man himself had captured.

But many people still couldn't understand how such an experienced outdoorsman had ended up meeting his demise just mere hours before he was due to head home.

Obviously, he would have been well versed in the rhyme which doubles as a safety reminder - "If it's brown, lay down. If it's black, fight back. If it's white, goodnight."

But this is clearly a load of hogwash, as it is believed that a male brown bear was responsible for killing the couple.

However, experts reckon there was a series of factors that day which could have ultimately led to his death.

The Katmai National Park's official investigation report on the incident stated: "Treadwell and Huguenard died from a bear attack that might have been avoided by adhering to basic principles of camping in bear country."

So, what are the four basic principles which the pair allegedly didn't abide by while cosying up to the beasts?

It's believe a brown bear killed the couple. (Getty stock photo)

Low visibility

Although there were no witnesses to the fatal attack, the national park believes Treadwell is likely to have stepped outside of his tent to investigate the presence of a bear nearby, before the animal pounced.

Katmai says that, at the time, 'the campsite and general area had poor visibility due to tall grass and heavy shrub cover'.

As well as making it harder for Treadwell and Huguenard to detect bears close by, it would also have affected the animal's visual ability.

If the brown bear was taken by surprise by the couple, it would have been more likely to react in a defensive way.

Too close for comfort

Treadwell liked to make the most of his annual camping trips and obviously wanted a front row seat for the action.

He pitched his tent in close proximity to the bears in a bid to increase their chances of running into one, but obviously this was an extremely dangerous position to be in.

Bear biologist Larry Van Daele explained that Treadwell and Huguenard were sitting ducks, as they were also close to a salmon stream where wild bears were known to feed from.

"The camp was set up in such a way that bears wishing to traverse the area would have had to either wade in the lake or walk right next to the tent," he said in the report.

"A person could not have designed a more dangerous location to set up a camp."

The animal lover is said to have made four fatal errors. (Lionsgate Films)

Time of year

The Grizzly Man had stayed on the campsite for longer than usual during his trip, meaning it clashed with the bears' bulking season ahead of winter.

In the October, the mammals will have been attempting to gain as much fat as possible before the cold months came in.

Food was also scarce for them during that autumn, so the bears were even more aggressive than usual.

The report explained that Treadwell was ambushed 'during a time of year when bears were fiercely competing for food sources', which undoubtedly encouraged the animal to launch its attack.

Food laid out

Despite being an accomplished outdoorsman, investigators believe that the 46-year-old may have made some silly mistakes with food storage which could have cost him his life.

The majority of Treadwell and Huguenard's supplies were kept in bear-resistant food containers (BRFCs), which officials say is the only time when grub can be left unattended.

Thee Interagency Grizzly Bear Committee approves bear resistant food containers and says they must be constructed of a solid non-pliable material capable of withstanding a minimum of 300 foot-pounds of energy.

Despite the couple using BRFCs, some snacks were also strewn inside their tent.

"It is possible that a bear investigated the camp in part due to the food found in the sleeping tent," Van Daele added.